Sorry for the length in advance, it's usually better to provide as much detail up front to help understand the problem clearly.
I have my Pi-Hole setup with a static IP, outside of the available IP range. 192.168.0.5, when the range is 192.168.0.10 - 192.168.0.200. This is the second Pi-Hole on my network. I removed the first one after I realized that I only needed a 2Gb Raspberry Pi to handle the traffic. So I removed the 8Gb that I started with. I transported my settings to the smaller device, from the bigger, and I changed the original IP address that I had set for the first from 192.168.0.187. I had this range reserved as well, from 192.168.9.10-192.168.0.150. I am new to Raspberry Pi and SSH, and at the time did not understand the concept, or how to log in. So I was using the WiFi and not eth0 initially thus the reason I went with the initial DHCP assigned 0.187 address. After I understood what I was doing I made the change to 0.5.
However, after I got the first one configured and connected via eth0 I was quite pleased with the results. I was blocking ~25% of the ad traffic and had in excess of 200,000 queries within 3 weeks with a block list of ~1.25M sites. The more important part is all of my devices picked up the Pi-Hole within 24 hours of getting it setup on eth0.
After I changed devices, however, I am over a week in and only about 1/3 of my network is using the Pi-Hole.
I have a 2Gb RP 4B, connected to eth0. My router is a TP-Link Archer C-4000. Both were running Raspbian 64Bit release. Both had SSH enabled. They were identical installs and configurations.
Router. The DNS settings for the primary and secondary DNS are OpenDNS IP. This is the way I have to enter them to work. If I attempt to enter the Pi-Hole IP I get an error message. So I am assuming this is the upstream DNS address once the Pi-Hole is accessed. In the Pi-Hole I have OpenDNS as the upstream.
To make the Pi-Hole work l have entered the IP in the under the DHCP settings for Primary DNS. Here is allows the entry and was working for all devices on my network before the change.
The only thing that I can think that might be a problem is when I was making the change I had the default pointing to OpenDNS while I was configuring and installing the 2Gb Pi, and that for some reason all of the devices that are not using the new Pi maintained the IpenDNS IP as their default and are now bypassing the Pi-Hole. But I am not a network engineer, so that is just speculation.
I have 19 lists running, with over 3.7M addresses blocked. I should be getting a much larger volume of traffic, and blocks so I can tailor the list.
Here is are a couple of before and after examples. Before the device change, both of my Roku TVs were trying to write to Roku server logs on an external address, the Pi-Hole blocked in excess of 5,000 of these queries. After the change neither device uses the device. I have two work computers with VPN access. Before the change my work computer had over 188,000 queries through the pi, after it still has not picked up the new device. Today there is only 1,400 queries. and 28% of those are blocked. It's a little concerning considering the only thing that I changed was the IP of the device and reduced the device size from 8Gb to 2Gb. Neither of which I would think, should have made that big of an impact on the routing.
Hopefully someone has encountered this and can help me understand what happened, and how to redirect all of my devices to the new device.
If you have any questions that I can provide answers to, please let me know.
Thanks for the help.